Preheat your smoker to 225 degrees F using oak or hickory wood for an authentic Texas flavor profile.
In a small bowl, combine the black pepper, sea salt, garlic powder, onion powder, and smoked paprika to create a dry rub.
Apply the rub generously to all sides of the beef brisket flat, pressing it into the meat to ensure it adheres well.
Place the brisket in the smoker and cook until the internal temperature reaches 165 degrees F, typically taking several hours.
While the meat smokes, whisk together the tomato paste, apple cider vinegar, and maple syrup in a small saucepan over low heat to create the glaze.
Remove the brisket from the smoker and wrap it tightly in butcher paper, then return it to the heat until the internal temperature reaches 203 degrees F.
Take the brisket out of the smoker and let it rest, still wrapped, for at least 30 minutes to allow the juices to redistribute.
Toss the green beans with olive oil and a pinch of salt, then roast at 400 degrees F for 15 minutes until they are tender and slightly charred.
Slice the rested brisket against the grain into thin strips and brush lightly with the prepared BBQ glaze before serving alongside the green beans.